The wide variety of consumer electronics devices available today such as, home computers, laptop computers, cellular telephones, personal data assistants (PDA) and personal music devices such as MP3 players rely upon microprocessors. Advances in the technology associated with microprocessors have made these devices less expensive to produce while improving their quality and increasing their functionality. Despite the improvements in microprocessors the physical user interfaces that these devices use have remained relatively unchanged over the years. Thus, while it is not uncommon for a home computer to have a wireless keyboard and mouse, the keyboard and mouse are quite similar to keyboards and mice commonly available a decade ago.
Cellular telephones and PDAs rely upon keypads that are functionally similar to those of analogous devices used many years ago. As the functions that PDAs support are now relatively complex the keypads that they support increasing have more keys. This represents a design constraint as the size of individual PDAs is reduced while the number of keys increases to the extent that users of these devices often have difficulty pressing desired keys on the keypad without pressing undesired keys. In some cases, the designers of cellular telephones have avoided this problem by limiting the number of keys on the keypad while associating specific characters with the pressing of a combination of keys. Due to its complexity, this solution is difficult for many users to learn and use.
In many instances the keypad and keyboard solutions for entering data are impossible for the user to access either through disabilities which can include visual impairment, motion impairment, or simply protective equipment for the environment they are working in.
The touch-pad, in the past decade has become common to laptops and palmtops as a means of removing the requirement for a separate mouse, such that motion of the users' finger provides for motion across the screen and a single tap selects a predetermined function. In laptops and palmtops this feature allows the user to move the cursor without the need for a physical supporting surface for a mouse, or adding a tracker ball or other element to the computer.
As originally contemplated, and subsequently implemented, for example in 1994 by Gerpheide (U.S. Pat. No. 5,305,017), and in 1995 by Boie et al (U.S. Pat. No. 5,463,388), the touch-pad is based upon the use of thin film materials to provide a means to detect a localized change in the electrical characteristics of the distributed electrical surface. As such the touch-pad allows for a user to provide control input signals based solely upon the motion of a users finger allowing the touch-pad to be easily deployed as a replacement for the computer mouse.
There has been relatively limited development of the touch-pad further in terms of capabilities and functionality. Amongst the limited development has been that of Holehan (U.S. Pat. No. 5,887,995) and Manser et al (U.S. Pat. No. 6,388,660). Holehan discloses the merging of a typical calculator or telephone keypad with a touch-pad, and as such presents a device wherein the traditional array of electrical contacts, one per key, is replaced with a touch-pad. However, the upper surface is now essentially the same flexible molded multiple key surfaces as seen on calculators and telephones. Manser takes the concept one step further by allowing for multiple membranes to be placed over the touch pad allowing the functionality to be adjusted from say calculator to mouse.
However, these require additional elements above and beyond the touch-pad, and are generally are designed to replicate traditional entry formats such as calculator keypads, and to be presented in a form and position typical of today's computer deployed touch-pads. A decade of development still offers us small flat rectangular touch-pads on a laptop with simple motion and single tap differentiation. It would therefore be advantageous to provide an interface for an electronic device which not only provided for a dynamic allocation of function, so that it can perform as numeric keypad, text keypad, pointing device and switch for example, but did so in a manner that facilities the integration of such a device into any small, lightweight and inexpensive electronic device.